A communication system may comprise a number of networks among which a user equipment may roam. For example, a wireless communication system may comprise a number of wireless networks, each wireless network being, for example, a public land mobile network (PLMN). A user equipment may be subscribed to a home network, referred as a home PLMN (HPLMN) and may roam to a visited network, referred to as a visited PLMN (VPLMN).
Typically, a user equipment may be allocated a Quality of Service (QoS) by the home network, that may, for example, include a Guaranteed Bit Rate (GBR), which may be allocated according to a service offered. In particular, a home network may provide services that require higher than normal quality of service to only a subset of its users, for example to users of high definition streaming video for large screen devices. However, when a user equipment is roaming, the visited network may offer only a default quality of service, that may not be satisfactory for users who are accustomed to receiving a higher quality of service from their home network.
In existing systems, it may be possible for a visited network and the home network to communicate to negotiate the provision of an appropriate quality of service for a user equipment by a signalling link, such as a “S9” link. However, such signalling links are not provided between all networks. Furthermore, even when a signalling link such as S9 is provided, the service offerings of the home and visited networks may differ, in particular in relation to video services, for which there are typically a large variety of coding/decoding schemes and encoding rates. As a result, the validation of quality of service provision rules using the signalling link may fail, and the visited network may apply default rules for a particular service. For example, a home network may wish to guarantee high definition (HD) H.264 video at 384 kbps, but if rule validation fails or the signalling link is absent, the visited network may provide the default guaranteed bit rate for H.264, which is 64 kbps, which may be too low for, in particular, large screen devices.